import { IncomingFile, StoredObject } from '../interfaces/file.interface';
import { StorageAdapter } from '../interfaces/storage-adapter.interface';
import { StorageConfig, UploadOptions, UrlMode } from '../interfaces/upload-options.interface';
export declare function createStorageAdapter(config: StorageConfig): StorageAdapter;
/** Facade over the active adapter: uploads, key/staging helpers, and urlMode-aware URL resolution. */
export declare class StorageService {
    readonly options: UploadOptions;
    readonly adapter: StorageAdapter;
    readonly urlMode: UrlMode;
    readonly stagingPrefix: string;
    readonly expiresIn: number;
    private readonly keyStrategy;
    constructor(options: UploadOptions);
    buildKey(input: {
        originalName: string;
        mime: string;
        category?: string;
    }): string;
    stagingKey(key: string): string;
    isStaged(key: string): boolean;
    permanentKey(key: string): string;
    upload(file: IncomingFile, key: string, meta?: Record<string, string>): Promise<StoredObject>;
    delete(key: string): Promise<void>;
    copy(src: string, dest: string): Promise<void>;
    exists(key: string): Promise<import("../interfaces/storage-adapter.interface").ExistsResult>;
    resolveDownloadUrl(key: string): Promise<string>;
    /**
     * Stamp a fresh `.url` next to every `.key` found at `path` (e.g. after an aggregation
     * `$lookup`). Mutates and returns `docs`. Works on a single object or an array.
     */
    resolveDownloadUrls(docs: any, opts: {
        path: string;
        expiresIn?: number;
    }): Promise<any>;
}